Effect of melatonin administration on cyclooxygenase-2 activity, serum levels of nitric oxide metabolites, lipoperoxides and glutathione peroxidase activity in patients with Parkinson's disease / Efecto de la administración de melatonina sobre la actividad de la ciclooxigenasa-2, la concentración sérica de metabolitos del óxido nítrico, los lipoperóxidos y la actividad de la glutatión peroxidasa en pacientes con enfermedad de Parkinson.

Objective: To determine the effect of melatonin (MEL) administration on ciclooxigenase 2 (COX-2) activity and serum concentration of nitric oxide metabolites, lipoperoxides and glutathione peroxidase (GPx) activity in patients with Parkinson's disease. Methods: Prospective double-blind randomized clinical pilot trial. 13 patients were included and two groups were formed: MEL at doses of 25 mg orally every 12 hours for 12 months and placebo with corn starch. Patients were assessed using the Unified Parkinson's Disease Scale. A blood sample was taken at baseline and every 3 months until 12 months. Results: COX-2 activity decreased as did nitrates/nitrites (3, 6 and 9 months) and lipoperoxides (9 and 12 months); GPx exhibited no significant differences.